Textile product manufacturing method and textile product

Abstract

To provide a method for producing a multilayered fiber product.SOLUTION: A method for producing a multilayer fiber product comprising at least two overlapping layers provides a first layer mainly comprising natural fibers and a second layer comprising synthetic fibers or particles in a web molding process, wherein the first layer and the second layer are molded by a foam molding process and joined together, and the first layer and the second layer are arranged in an overlapping relationship, the second layer is capable of imparting heat sealing properties to the textile product.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a method for producing a textile product according to the preamble of claim 1.

[0002] In this type of method, a base layer comprising mainly natural fibers is prepared to prepare a multi-layer textile product. It is formed in a web forming process, bringing the heat seal layer onto the base layer.

[0003] The invention also relates to a textile product according to claim 20 and to a use according to claim 26. [Background technology]

[0004] Today's consumers are increasingly demanding environmentally friendly packaging solutions. For many retail chains and brand owners, products like paper and paperboard are renewable. It is a preferred packaging material because it is obtained from raw materials that are readily recycled. Many packaging applications that require excellent barrier properties against grease, water, and oils require heat seal properties. Therefore, the paper and plastic laminate is It is frequently used in packaging for confectionery and bakery products. Such laminates are made by extruding paper. By coating or by cold or hot bonding paper with plastic film It is produced by laminating using a coating agent.

[0005] To bond extruded films to paper or paperboard substrates and to strengthen laminate films Because of the need for increased strength, the percentage of plastic in these film laminates is often This makes it difficult to pulp the material, and recycling is often difficult. For example, in extrusion coating of paper, the specified thickness Thinner films make it difficult to obtain sufficient adhesion of the film to the paper, so plastic The minimum thickness of the stick film is usually about 15 μm. The film must be self-supporting, so the thickness must be less than 20um for lamination. It is difficult to attach the film.

[0006] Finland Patent Invention No. 126474 describes a thermoplastic fiber reinforced fiber. can be incorporated as a heat seal agent, thereby imparting heat seal properties to the product. However, the matrix does not contain any natural fiber matrix. The amount of such reinforcing fibers mixed is sufficient to provide good heat sealability. It should be relatively high.

[0007] For example, due to the above-mentioned shortcomings of the conversion process and materials of the present invention, current heat seal Paper materials contain a relatively large amount of plastic which impairs the recycling of the material. The production of such materials generally requires one or more additional process steps, Strikes increase.

[0008] Furthermore, heat-sealed products based on plastic films are not breathable. However, many packaged products, e.g. powder products, require packaging time due to the efficiency of the packaging line. Many products, such as textiles and furniture, require ventilation during storage and transportation. Aeration or ventilation of the product is desirable. Bakery products such as bread benefit from breathable packaging. This reduces delivery time by eliminating the need to cool the product before packaging. This is because. Summary of the Invention

[0009] The object of the present invention is to obviate at least some of the problems associated with the art and to provide a new type of and a method for producing the heat-sealed textile product. .

[0010] In particular, reduce the amount of thermoplastic materials incorporated into products and promote the production of recyclable packaging materials. Improve the recyclability of heat-seal paper-type materials by making their manufacturing more cost-effective. The purpose is to

[0011] A further object of the present invention is to produce a final product with novel heat seal and air permeability. The object of the present invention is to provide a method for producing the same.

[0012] According to the invention, a substrate layer comprising mainly natural fibers is coated with mainly synthetic fibers or particles, in particular synthetic fibers or particles. A heat seal layer comprising long synthetic fibers is formed.

[0013] In the present invention, such separate heat-sealable fibrous layers allow the overall thickness of the layers to be significantly reduced. It has been found that it is possible to reduce the total amount of synthetic material. On the other hand, the heat generated is usually stronger than that obtained with conventional extrusion coating or laminating films. The same amount of synthetic fibers or particles are uniformly incorporated into the base layer. The materials of the present invention provide a heat seal that is stronger than that obtained with conventional products and can be bonded with other materials. will be done.

[0014] In the method according to the invention, the layers, in particular the heat-sealing layers, are formed in the web-forming step. already provided on the substrate layer, whereby the heat-sealable fibrous layer does not need to be attached to any completely separate process. It is strongly adhered to the substrate layer without the need for process steps or lines.

[0015] According to the invention, preferably at least one of the layers, in particular at least one substrate layer or At least one of the heat seal layers, or both, are formed by foam molding.

[0016] More specifically, the method according to the invention is based on what is stated in the characterizing part of claim 1. It has the following characteristics.

[0017] The product according to the invention is then characterized by what is stated in the characterizing part of claim 20. .

[0018] The use according to the invention is defined in claim 26.

[0019] The present invention provides significant advantages.

[0020] In particular, the present invention allows the production of paper-plastic laminates, which are commonly used as packaging materials. The proportion of new plastic materials can be significantly reduced by up to 75% compared to conventional products. This is because the heat seal layer, which is rich in fibers or particles, is used to form the product during the web forming step. due to the fact that it can be produced as a very thin structure that adheres firmly to the substrate layer. The present invention therefore allows for the production of multi-layer materials that are easier to recycle. Because the present invention removes one separate purification process from the manufacturing chain, the present invention also It also allows for cost-effective production of heat seal materials.

[0021] Additionally, existing plastics where synthetic thermoplastic fibers are uniformly mixed throughout the fiber matrix Compared to the stick imitation product, the heat seal according to the present invention requires the same starting material and total amount of It was found to be up to 60% stronger than those with the material. It allows the use of plastic materials, making it easier to recycle materials and in the packaging industry. This allows for the production of strong seams, which is essential.

[0022] Compared to products manufactured by lamination or extrusion coating methods, self-contained frames Unlike film, the heat-sealed fiber layer in addition to the base layer is also breathable. This provides the advantage that the product is breathable.

[0023] Preferably, both the base layer and the heat seal layer are such that the dry matter content of the product is still low ( When the thickness of the layers is less than 35%, they are formed and attached to each other in a foam molding process. The sealing is achieved by adding a binder to the layers or at least to their interface zones. The binders used may be further reduced in need of synthetic fiber materials. Preferably, it is heat-sealable by itself. The darning process ensures a sufficiently strong interconnection.

[0024] The thickness of the heat seal layer is usually much less than the thickness of one of the base layers and is 15 g / m 2 Less than 10 g / m 2 Less than 5g / m, more preferably 2 It has the following basis weight: It is a heat seal layer.

[0025] The absolute thickness of the heat seal layer is preferably 10 μm or less, for example, 2 to 10 μm. This is significantly less than can be obtained with conventional heat-sealed products.

[0026] In the following, preferred embodiments of the present invention will be considered in more detail based on the accompanying drawings, in which: . [Brief explanation of the drawings]

[0027] [Figure 1A] 1 is a cross-sectional view of a two-layer multi-layer textile structure according to one embodiment of the present invention. [Figure 1B] 1 is a cross-sectional view of a three-layer multilayer textile structure according to one embodiment of the present invention. [Figure 1C] 1 is a cross-sectional view of a multi-layer fibrous structure according to one embodiment of the present invention, in which the base layer and the heat seal layer are partially intermixed with each other to strengthen the interlayer bonding in the structure. [Figure 2] 2A-2B are flow charts of the inventive manufacturing method according to two embodiments of the invention. [Figure 3] 1 graphically illustrates the results of the strength tests described in Example 1. DETAILED DESCRIPTION OF THE INVENTION

[0028] In this context, the term "layer consisting mainly of X" (or "mainly comprising") means This means that the layer comprises at least 50% by weight of material X.

[0029] The term "heat seal" refers to the act or action of a material with at least another similar structure and material. refers to structures and materials that can be formed into a permanent seal under heat and pressure.

[0030] The terms "web forming process" and "forming" refer to the process where the raw materials in the final product are A wet-processed web-like material that is introduced onto the wire in the form of a slush or foam. represent the formation of various fiber-based structures, which provide the final fibrous matrix. formed or shaped into a fibrous web that is then dried in the drying section of a paper or paperboard machine "Foam molding" refers in particular to the process disclosed in Finnish Patent No. 126474. It means the way in which

[0031] The term "long" when applied to synthetic fibers generally refers to a length of at least 1 mm. It means a fiber having

[0032] The term "multilayer web" in "multilayer textile product" refers to a web of at least two overlapping layers of fibers. It refers to a web or textile formed by layers. There will usually be 2 to 10 layers, especially 2 or 3 layers. At least one of the layers forming the surface of the article is formed by a heat seal layer. In this configuration, the layer adjacent to the heat-sealable layer usually does not itself have heat-sealable properties. In addition to the fibrous layer, a preselected property, e.g., hydrophobicity, may be added to the layered product. There may also be a surface layer that provides

[0033] The "fiber length" in "average fiber length" is expressed as a length-weighted average. The length-weighted average fiber length is the length of each It is calculated as the sum of the squares of the fiber lengths divided by the sum of the individual fiber lengths.

[0034] As is apparent from the above, in the manufacturing method of the preferred embodiment, the heat seal layer of the paper material is delivered onto a product already in production to provide a multi-layer product. Such multi-layered fiber products are typically made from, for example, chemical pulp, mechanical pulp, semi-mechanical pulp, recycled pulp, a base layer, e.g., comprising primarily natural fibers such as raw fibers or any combination thereof; a first layer and a web forming process comprising primarily synthetic fibers, particles, or a combination thereof; and a second layer, ie, a heat seal layer, which is molded onto the first layer by a process.

[0035] In one embodiment, a method for producing a multi-layer textile product comprising at least two overlapping layers is provided. This is achieved in particular by a web forming process using foam molding. a first layer comprising primarily natural fibers is provided; and a second layer comprising synthetic fibers or particles is provided; The first and second layers are disposed in an overlapping relationship. The second layer is configured to provide a heat seal to the textile. The properties of the rule can be given.

[0036] In one embodiment, the first layer is formed into a web from a first slush having a first composition; and The second layer is formed from a second slush having a second composition, the web formed by the first layer. and forming a multi-layer web.

[0037] The first and second compositions may comprise at least one selected from, for example, fibers, polymers, additives, and water. At least one of the compositions, in particular the Preferably, both contain a blowing agent.

[0038] In one embodiment, the first and second layers are formed in a foam molding process using a multi-layer headbox. The molded pieces are then molded and bonded together.

[0039] According to one embodiment, the multilayer textile product of the present invention comprises, for the production of at least the base layer: Also preferably, foam molding techniques are used for the production of heat-sealed layers and for interconnecting the layers. Generally, this technology is described in the document Finnish Patent No. 126474. and Finnish Patent No. 126092. This allows for even distribution of long synthetic fibres in thin layers, resulting in a high quality end product. can be obtained.

[0040] In one embodiment, the foam molding of the multi-layer product of the present invention is carried out by supplying the foam flow in layers or in parts. This is carried out using a single forming unit.

[0041] The forming unit can be horizontal or vertical. For example, for a two-layer web, one The foam stream forms the base web. The dried product of the stream comprises mainly natural fibers. The other forming layers comprise primarily thermoplastic fibers.

[0042] Generally, foaming results in a higher consistency of the furnish (higher dry matter content of the slush). ) can be maintained. Typically, in this technology, the consistency in the head box is 0.1 wt. %, in particular greater than 0.5% by weight, up to about 3% by weight.

[0043] In a preferred embodiment, a portion of the starting material is initially prepared by mixing a first aqueous phase with a mixture of primarily natural fibers. and a first fibrous phase comprising the first fibrous phase and the second fibrous phase comprising the second fibrous phase. The foam comprises a foam or water foaming liquid and at least one foaming agent, as described below. The heat seal layer is formed by foam molding by dispersing the fibers. As a mixture or dispersion, in particular, synthetic fibers and any particles of the second fiber phase are dispersed in the first fiber phase. By allowing the second aqueous phase and the natural fibers to at least partially penetrate between the fibers, A foam portion comprising a second fiber or particle comprising primarily synthetic fibers or a combination thereof. It is applied to the base web as a web or foamed dispersion.

[0044] The resulting wet-laid multi-layer web is dried to remove water, thereby allowing the natural and synthetic fibers to coexist. Similarly, one or more binders are added to the first and / or second layers to form a layered fiber matrix. The binder can be applied to the second aqueous phase or to the entire web, whereby the binder is also present. Preferably, the binder is compatible with the fibers and particles of the heat seal layer. It is selected to be.

[0045] In general, the ratio of the foam flow velocity to the wire velocity (if possible, already in the first slash) The σ (a layer of which may be deposited) ranges from 0.1 to 2.5.

[0046] In one embodiment, the ratio is not equal to 1. In that embodiment, the ratio is 0.01 to 0.02, which allows for the development of interlayer bonds. The layers are intermixed on the wire to achieve this.

[0047] In one embodiment, this ratio is greater than 1 and up to 2.5.

[0048] In one embodiment, the foaming process is carried out using a mixture of typically 0.1 to 15% by weight, for example 0.5 to 10% by weight. To obtain a fiber foam comprising at least one foaming agent, a foaming liquid of foam or water and a small amount of forming a foam dispersion by dispersing fibers in at least one foaming agent. The fiber foam thus formed is then transferred to a perforated support such as a wire. The liquid is then expelled through the foraminous support to form a sheet.

[0049] The foaming agent for producing the foam is selected from surfactants that allow the foam to be formed. Therefore, the blowing agent is usually a water-soluble foaming polymer agent and a water-dispersible foaming polymer agent, as well as The foaming agent may be selected from a water-soluble glycan, a water-dispersible glycan, a water-soluble ... Selected from water-soluble hydrophilic polymers and water-dispersible hydrophilic polymers and combinations thereof Preferably, the water-soluble glycans and water-dispersible glycans are polysaccharides and The water-soluble hydrophilic polymer and the water-dispersible hydrophilic polymer are selected from the group consisting of poly(ethylene glycol) and poly(ethylene glycol). Poly(vinyl alcohol) and poly(vinyl acetate) and copolymers thereof You can also do this.

[0050] In one embodiment, if the fibers do not form hydrogen bonds, the foaming chemical acts as a binder. also works.

[0051] In one embodiment, the layer formed from the first slush from the first headbox is first It dries and is then fed from the second headbox onto the still wet first layer before the second layer is deposited. It is possible to remove some, usually the majority, of the water from the Thus, in one embodiment, the first layer is formed into a web having a first solids content; The web is modified to have a second solids content (second dry matter content) by increasing the solids content of the web. dried to provide a quality web, A second layer is applied over the modified web.

[0052] Similarly, especially when using separate headboxes, the first layer is formed into a web having a first solids content; The web is modified to have a second solids content (second dry matter content) by increasing the solids content of the web. To provide a high quality web, the press in the press section and the cylinder section are Linder drying or a combination thereof, A second layer is applied over the modified web.

[0053] The first layer initially has a high moisture content, such as the first water composition used to form the web; The modified water composition is dried to a higher solids content (dry matter content) before the second water composition is deposited. For example, the first layer may contain 15 to 35% by weight, particularly 20 to 35% by weight, of the second solid. It is dried to form content to form the modified web before applying a second layer onto the web.

[0054] In one embodiment, drying of the web, particularly the multi-layer web, is accomplished by non-contact drying.

[0055] Drying methods include vacuum drying, hot air drying, ventilation drying, far-infrared drying, cylinder drying, and and combinations thereof. do.

[0056] Drying is usually done to a final moisture content of less than 20% by weight, usually less than 15% by weight, especially less than 10% by weight. This is continued until the content is reached.

[0057] In one embodiment, the particles (including fibers) of the layer have a size larger than the pore size of the wire. This allows for the use of a vacuum to facilitate the removal of water from the web.

[0058] The binder may be applied to a partial web or a multi-layer web, i.e., a base layer web and and heat seal layers separately on the web before or after bonding them together. The structure can be achieved by applying a tensile strength test to one or both layers at the interface of the layers before joining the webs together. Strengthened by applying a binder to one of the webs, usually on their contact surface. can.

[0059] In one embodiment, both the base layer and the heat seal layer comprise the same thermoplastic binder. , suitably spread evenly on or within the layer.

[0060] The hydrophobicity of the products degraded herein can be further improved. Thus, in one embodiment In the case of the present invention, a hydrophobic layer is disposed on the surface of the base layer opposite the heat seal layer. An example is a surface lacquer layer.

[0061] Alkylene ketene dimer (AKD), alkenyl succinic anhydride (ASA), binder By using hydrophobic agents such as PEG-100 in combination with cross-linking agents, the surface layer of a multi-layer product can be It can be given hydrophobic properties.

[0062] With regard to the fibrous and particulate materials of the layers, the following may be mentioned:

[0063] In this context, in particular, natural fibers are those which have been chemically or semi-chemically pulped or or defibration, derived from cellulosic or lignocellulosic feedstocks. The fibers can also be mechanical pulp fibers or regenerated fibers. In particular, natural fibers are Natural fibers and It refers to a mixture of these.

[0064] The raw materials for cellulose or lignocellulosic fibers are wood, annual and perennial plants. Wood and plant materials can be used, especially deciduous woods (e.g. birch, aspen). obtained from chestnut, poplar, alder, eucalyptus, or mixed tropical hardwoods) or especially from conifers Wood is used as raw material. Examples of the latter include wood obtained from spruce or pine. can be.

[0065] The cellulosic or lignocellulosic fibers can be purified.

[0066] In one embodiment, unrefined cellulosic or lignocellulosic fibers, particularly cellulose fibers is used.

[0067] In one embodiment, the base layer (substrate layer) is primarily made of natural fibers. The base layer (substrate layer) shall not exceed 50% by weight, calculated from the total weight of the fibers in the base layer (substrate layer). It contains up to 100% natural fibers by weight.

[0068] In one embodiment, the base layer (substrate layer) contains 1 to 49% by weight, typically about 1 to 30% by weight, e.g. For example, it may comprise about 1 to 20% by weight of other fibers, particularly synthetic fibers.

[0069] Further ingredients, such as binders or other additives, and additives to the product or manufacturing process Other ingredients that may be required may also be incorporated. The amounts of such ingredients may vary. , generally about 0.1 to 30 parts by weight per 100 parts by weight of the layer.

[0070] Examples of binders include natural binders such as starch and modified starch and starch derivatives. binders and biopolymers, chitosan, alginate, and vinyl acetate and vinyl Synthetic binders such as acrylate latex, polyurethane and SB-latex and their mixtures and various copolymers, especially copolymers of synthetic binder polymers. Polymers are included.

[0071] The heat seal layer is made of polylactide (PLA), glycolic acid polymer, and polyolefin. , polyethylene terephthalate, polyester, polyamide, polyvinyl alcohol or thermoplastic fibers and / or particles, such as bicomponent (bico) fibers or particles particles up to 100% by weight, for example 50-100% by weight, for example 51-99% by weight In particular, the material may be PLA, polypropylene (PP), polyethylene (PE) or It can also be a monocomponent fiber. Other fibers such as polybutylene succinate (PBS) can also be used. The above-mentioned biopolymers are also polymers that can be made into these synthetic fibers or synthetic particles. One example is PLA-PBS multilayer synthetic fibers or particles. It may be a degradable thermoplastic fiber.

[0072] As a raw material for the heat seal layer, for example, up to about 50% by weight, for example, from about 0.1 to about 50 Less than 1 to 49% by weight (for example, 1 to 49% by weight) of long reinforcing fibers, especially viscose, or natural fibers Any other fiber or non-thermoplastic synthetic fiber may be used. Thus, for example: The above types of (and purified, or preferably unrefined) cellulose or lignocellulosics are Cellulose fibers can be incorporated into the heat seal layer. Typically, the amount of such fibers is is up to 40% by weight, particularly about 5 to 30% by weight.

[0073] The synthetic fibers of the heat seal layer may have a density of, for example, 10 dtex or less, preferably 5 dtex or less. The average length of the long fibers may be, for example, 1 to 50 mm. , preferably 1 to 20 mm, for example 3 to 12 mm. The length mass of A fiber is 1.7 dtex and the length is 6 to 12 mm.

[0074] Binders and / or other additives necessary for the product or manufacturing process may also be incorporated. The amount of such components is generally about 0.1 to 30 parts by weight per 100 parts by weight of the layer. .

[0075] Examples of binders include starch and modified starches and starch derivatives, chitosan, Natural binders and biopolymers such as alginates, vinyl acetate and vinyl acrylate - Synthetic binders such as latex, polyurethane and SB-latex, and various copolymers, such as copolymers of the same and their mixtures, and in particular of synthetic binder polymers. In one embodiment, a heat-sealable binder is used. In an embodiment, a polymer that can impart elastic properties to the heat seal layer, such as polyurethane, is used. A lower is used.

[0076] The interconnection of the layers is carried out, for example, at a temperature of at least 90°C, preferably above 130°C. It can also be accomplished thermally by calendering the multilayer web with can also be improved by doing so.

[0077] In one embodiment, the aqueous composition of the first layer (the "first slush") comprises natural fibers, optionally In addition to synthetic fibers and / or particles, if necessary, 0.1 to 15% by weight calculated from the solid content, It also includes an additive selected from surfactants, binders, and combinations thereof.

[0078] In one embodiment, the aqueous composition of the second layer (the "second slush") is made of synthetic fibers and / or or particles, and other fibers such as natural fibers, if necessary, calculated from the solid content. 1 to 15% by weight of the content, selected from surfactants, binders and combinations thereof Contains additives.

[0079] As is apparent from the above, in one preferred embodiment, the first layer is "non-heat sealable." that is, it cannot be heat sealed to another similar layer, while the second layer The layer can be heat sealed to the other layer.

[0080] Turning now to the drawings showing various embodiments in more detail, FIG. 1A shows a base layer 12 ("base"). a heat seal layer 14 disposed on the first surface of the base layer; FIG. 1B shows a basic structure having a second surface opposite the base layer. An embodiment is shown in which a functional surface layer 16 is disposed. This second surface layer 16 can be, for example, a heater. with a hydrophobic layer to provide both waterproof and improved moisture barrier properties to the final product. could be.

[0081] Generally, the heat seal layer 14 is thinner than the base layer 12. Its basis weight is typically 10 g / m 2 Preferably 1 to 5 g / m or less 2 , for example, 2 to 4 g / m 2 and the basis weight of the base layer is 20 to 100 g / m 2 , for example 30 to 70 g / m 2 , especially 20-60g / m 2 or 20~40g / m 2 In one embodiment, 70 g / m 2 Multilayer products (sheets or Web) is 60g / m 2 10g / m overlapping fibrous base layer 2 The heat seal layer In another embodiment, the base layer has a basis weight of 30 g / m 2 , Heath The basis weight of the roll layer is 3 g / m 2 A multi-layer product was produced.

[0082] As mentioned above, the base layer may comprise 50 to 100% by weight, for example 51 to 99% by weight, of natural fibers. , typically cellulose or lignocellulosic fibers.

[0083] In one embodiment, the multi-layer structure shown in the drawings is a multi-layer head box configured for foam molding. It is produced on a paper or board machine by using cox.

[0084] Referring to FIG. 2A, according to one embodiment, a partial web and heater forming a base layer are used. The partial webs forming the seal layer are formed in steps 21A and 21B of the foam molding process. , formed from different masses using the multi-layer headbox of the paper machine, and then in step 2 In step 2, a multi-layer web is formed from the partial webs.

[0085] To prepare a multi-layered fibrous product, the multi-layered web is further dried in step 23. In response, in steps 21A and 21B, a binder is applied to the partial web. Additionally or optionally, a binder may be applied to the multi-layer web. The multi-layer web can also be calendered to improve interconnection of the layers.

[0086] Referring to FIG. 2B, according to one embodiment, the base web forming the base layer is a foamed The web is then formed in step 26 by molding, followed by a web forming step to produce a multi-layer web. During the forming step, at step 28, a thermoplastic synthetic fiber is applied to the surface of the web forming the base layer. Before this, a binder is applied to the base web in step 27. Finally, in step 29, a multi-layer web can be formed to produce a multi-layer textile product. Dry.

[0087] To achieve the required layer strength, foam molding is carried out in particular in conjunction with web molding. , it is possible to adjust the mixture between the different layers.

[0088] According to one embodiment illustrated in FIG. 1C, a base layer 12C and a heat seal layer 14C The fibers are intermixed at the interface zone of the layers so that the interface of the layers is "slippery." The thickness of the face zone 13C is, for example, 5 to 50% of the thickness of the heat seal layer 14C, e.g. The thickness can be 0.5 to 3 um. By mixing, the adhesive strength is strengthened and the adhesive strength is increased throughout the product, especially from the product. This strengthens the heat seam that is created and also promotes intermixing with the other layers of the product. If desired, the multi-layer structure may be formed by separating the layers so that the layers are not substantially intermixed with each other. It can also be produced by foam molding.

[0089] The base layers 12, 12C are referred to in this unit, but in general the base layers also have some According to one embodiment, the base layer 12, as well as the heat seal layer, 12C, however, comprises a substantially single layer and has a homogenous fiber composition. [Example]

[0090] (Example 1: Effect of layer structure on heat sealability) Using a sheet mold, the first layer on the wire side is made of 100% cellulose fiber and the second layer is made of cellulose fiber. The adjacent layer, i.e., the heat shield, is made of a blend of cellulose and polylactide (PLA) fibers. A sheet was prepared comprising a first non-heat seal layer and a second non-heat seal layer. The layer was applied at a temperature of 90°C using one nip and a pressure of 10 bar. Calendared.

[0091] The sheets were seamed with a force of 800 N, a temperature of 210°C and a heat seal time of 0.5 seconds. The strength of the seams was measured with a horizontal traction device using 50 mm wide sample strips. The strips were cut horizontally from the sheet with the seams running vertically. The strip drawing speed was 20 mm / min and the drawing gap was 100 mm. Three to four parallel measurements were performed on the samples.

[0092] The same total amount of samples (1a, 2a, 3a, 4) and reference samples (1b, 2b, 3b) materials were used, however in the samples, synthetic fibers were a fraction of the amount of cellulose fibers. In this way, a layer structure more similar to that described above was produced. In the reference sample, the synthetic fibers were mixed uniformly with the total amount of cellulose fibers.

[0093] Details of the materials and results are shown in Table 1 and Figure 3.

[0094] [Table 1]

[0095] The results for samples (1a, 2a, 3a, 4) and reference samples (1b, 2b, 3b) As can be seen from the figure, when synthetic fibers are laminated to one side of the sheet, the PLA fibers are The seam strength was increased by at least 60% compared to the situation where the seams were evenly distributed throughout the structure.

[0096] Sample 4 is a thin (5 g / m) woven fabric on top of a natural fiber base layer. 2 ) Heat seal layer Therefore, it is clear that the current seam is strong enough for practical use. The strength of the textile is improved by using a significantly lower amount of synthetic polymer than when the polymer is mixed uniformly throughout the textile. The above structure can be achieved using synthetic polymers. [Industrial Applicability]

[0097] The product according to the invention may be, for example, a heat-sealed product having at least one heat-sealed seam. Can be used as a seal packaging blank or packaging like bag or bow do. [Prior art documents] [Patent documents]

[0098] [Patent Document 1] Finnish Patent Invention No. 126474 (FI 126474 B) [Patent Document 2] Finnish Patent Invention No. 126092 (FI 126092 B) [Patent Document 3] Finnish Patent Specification No. 63806 (FI 63806) [Patent Document 4] European Patent No. 195458 (EP 0 195 458 B1)

Claims

1. 1. A method for making a multi-layer textile product comprising at least two overlapping layers, comprising: a first layer containing primarily natural fibers; a second layer including synthetic fibers or particles, and wherein the first layer and the second layer are formed and bonded together in a web forming process, the first layer and the second layer being disposed in an overlapping relationship, and the second layer being capable of imparting heat seal properties to the textile; the first layer comprises more than 50% by weight and up to 100% by weight of natural fibers, calculated based on the total weight of fibers contained in the first layer; and the second layer contains 50% by weight or more of the synthetic fibers or particles, calculated based on the total weight of the fibers contained in the second layer; The following steps are carried out: the first layer is formed into a web having a first solids content; the web is cylinder dried in a cylinder section or pressed in a press section and cylinder dried in a cylinder section to increase the solids content of the web and provide a modified web having a second solids content; the second layer is applied to the modified web; method.

2. the first layer is formed into a web from a first slush having a first composition; the second layer is applied from a second slush having a second composition onto the web formed by the first layer to form a multi-layer web; 10. The method of claim 1, wherein the first composition is different from the second composition, and at least one, preferably both, of the first and second layers are formed by foam molding.

3. 3. The method of claim 1 or 2, wherein the first and second layers are formed and bonded together in a foam-forming process, preferably using a multi-layer headbox.

4. 4. The method according to claim 1, comprising providing, by drying, a modified first layer having a dry matter content of 15 to 35% by weight, in particular 20 to 35% by weight, before applying the second layer to the first layer.

5. The method of any one of claims 1 to 4, wherein the second layer is applied onto the modified web in the form of a foam.

6. The method of any one of claims 1 to 5, wherein the multi-layer web formed by the first layer and the second layer is dried to produce a multi-layer fibrous product.

7. The method of claim 6, wherein the drying of the multi-layer web is accomplished by non-contact drying.

8. The method according to claim 6 or 7, wherein the drying is carried out by at least one method selected from the group consisting of vacuum drying, hot air drying, ventilation drying, far-infrared drying, and combinations thereof.

9. 9. The method according to any one of claims 1 to 8, wherein the first layer is formed from a first slash comprising natural fibers selected from cellulose and lignocellulosic fibers and combinations thereof, in particular the first slash comprising those combinations of cellulose or lignocellulosic fibers obtained from annual or perennial plants, in particular wood.

10. 10. The method of any one of claims 1 to 9, wherein the second layer is formed from a second slush comprising thermoplastic fibers or particles selected from polylactide, glycolic acid polymer, polyolefin, polyethylene terephthalate, polyester, polyamide, polyvinyl alcohol, polybutylene succinate and combinations thereof, in particular the second slush comprising biodegradable thermoplastic fibers selected from polylactide or polylactide-polybutylene succinate fibers.

11. 11. A method according to any one of claims 1 to 10, wherein the second layer is formed from a second slush comprising thermoplastic fibres having a fineness of at most 10 dtex, preferably at most 5 dtex, such as from 1 to 5 dtex, and an average length of 1 to 50 mm, preferably from 1 to 12 mm, such as from 6 to 12 mm.

12. 10. The method of claim 2 or 9, wherein the first slush, in addition to the natural fibers, also comprises 0.1 to 15% by weight, calculated on the solids content, of additives selected from surfactants, binders, and combinations thereof.

13. 13. The method of any one of claims 1 to 12, wherein the second layer is formed from a second slush comprising, in addition to synthetic fibers, 0.1 to 15% by weight, calculated on the solids content, of an additive selected from a surfactant, a binder, and combinations thereof.

14. 14. The method according to any one of claims 2 and 9 to 13, wherein the first slush or the second slush or both comprise at least one binder, in particular a thermoplastic binder, selected from the group of natural binders and biopolymers comprising at least one of starch or modified starch or derivatives, chitosan, alginate, or synthetic binders comprising at least one of vinyl acetate and acrylate latex or polyurethane or SB-latex, polyvinyl alcohol or polyvinyl acetate, or any mixture of these binders or copolymers.

15. 15. The method of any one of claims 1 to 14, wherein the first layer or the second layer or both are impregnated with a binder.

16. 16. The method according to any one of claims 1 to 15, wherein the second layer comprises up to 100% thermoplastic fibres and / or particles, calculated from the total weight of the second layer.

17. 17. The method of any one of claims 1 to 16, wherein the web forming process comprises a foam forming process.

18. 18. A multi-layer textile product for use as textile packaging, textile sheets or textile webs, obtainable by the method according to any one of claims 1 to 17, A base layer made primarily of natural fibers and a heat seal layer disposed on the base layer, the heat seal layer is mainly composed of synthetic fibers or particles, the base layer comprises more than 50% by weight and up to 100% by weight of natural fibers, calculated based on the total weight of fibers in the base layer; and The heat seal layer contains 50% by weight or more of the synthetic fibers or particles, calculated from the total weight of the fibers contained in the heat seal layer. A product characterized by:

19. 19. Product according to claim 18, wherein the heat-sealable layer consists mainly of biodegradable thermoplastic fibres having a fineness of at most 10 dtex, preferably at most 5 dtex, for example 1-5 dtex, and an average length of 1-12 mm, preferably 1-12 mm, for example 6-12 mm.

20. The basis weight of the heat seal layer is 10 g / m ２ and the basis weight of the base layer is 20 to 100 g / m ２ 20. The product of claim 18 or 19,

21. 21. The product of claim 18, wherein a hydrophobic surface layer is disposed on the surface opposite to the heat seal layer or the base layer, the surface layer comprising alkylene ketene dimer (AKD), alkenyl succinic anhydride (ASA), or a combination of a binder and a cross-linking agent.

22. 22. The product of any one of claims 18 to 21, wherein both the base layer and the heat seal layer comprise the same thermoplastic binder, spread evenly on or within said layers.

23. 23. The product of any one of claims 18 to 22, wherein the product comprises at least one sheet folded to form a package, and wherein the sheet comprises at least one seam area in an area where the sheet is attached to itself or another sheet by heat sealing.

24. 24. The product of any one of claims 18 to 23, wherein the heat-sealable layer consists primarily of thermoplastic synthetic fibers.

25. 25. Use of a product according to any one of claims 18 to 24 as a heat-sealed or heat-seamed packaging material.

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